while(True):

    tues_or_thurs = {'h': 'thursday', 'u': 'tuesday'}

    weekend = {'a': 'saturday', 'u': 'sunday'}

    week = {'t': tues_or_thurs, 's': weekend,
            'm': 'monday', 'w': 'wensday',
            'f': 'friday'}

    first_char = input('请输入第一位字母：').lower().strip()


    if first_char in ['a', 't', 's', 'm', 'w', 'f']:
        if week[first_char] == tues_or_thurs or week[first_char] == weekend:
            second_char = input('请输入第二位字母：').lower().strip()
            if second_char in ['u', 'h', 'a']:
                print(week[first_char][second_char])
            else:
                print('请输入正确字母')
        else:
            print(week[first_char])
    else:
        print('请输入正确的字母')